Work feeding mechanism for sewing machines



Oct. 31,1967

S.J KETTERER ET AL 3,34%735 WORK FEEDING MECHANISM FOR SEWING MACHINES Filed June 14, 1965 5 Sheets-Sheet 1 Oct. 31, 1967 5. J. KETTERER ET AL 34%{735 I WORK FEEDING MECHANISM FOR SEWING MACHINES Filed June 14, 1965 3 Sheets-Sheet 2 WITNESS.

ATTORNEY.

J. KETTERER ET AL, iw fi fififi WORK FEEDING MECHANISM FOR SEWING MACHINES Filed June 14, 1965 Oct. 31, 1967 3 Sheets-$heet 5 WITNESS.

a W l United States Patent 3,349,735 WORK FEEDING MECHANISM FOR SEWING MACHINES Stanley J. Ketterer, Morris Plains, N.J., and George F. Keller, deceased, late of Lake Mohawk, Sparta, N.J., by Marion A. Keller, executrix, Lake Mohawk, Sparta, N.J., assignors to The Singer Company, New York, N.Y., a corporation of New Jersey Filed June 14, 1965, Ser. No. 463,969 12 Claims. (Cl. 112-214) ABSTRACT OF THE DISCLOSURE Sewing machine work feeding mechanisms are disclosed in which annularly arranged work feeding elements to present work feeding surfaces substantially coplanar with a work supporting surface on the machine frame. The Work feeding elements are opposed laterally opposite the stitching point of the sewing machine by a presser device so that as the work feeding elements are moved in a closed path following the annular arrangement thereof work feed in a substantially straight line tangentially of the annular array of work feeding elements is obtained.

This invention relates to sewing machines and, more particularly, to a novel and improved work feeding mechanism for a sewing machine.

It is an object of this invention to provide a novel mechanism for advancing work fabrics intermittently relatively to the stitching point of a sewing machine with advantageous consistency.

It is also an object of this invention to provide an improved sewing machine work feeding mechanism of which the operation results in a minimum of sewing machine vibration.

A further object of this invention is to provide a sewing machine work feeding mechanism into which the leading edge of a work fabric panel may be readily introduced, and into which work fabric portions of suddenly increased thickness, such as cross seams or the like, will be admitted without ancillary effort and advanced with great uniformity.

This invention comprehends the employment of one or more intermittently rotated work feeding disks journaled on axes perpendicular to the sewing machine work supporting surface and laterally of the stitching point. A roughened annular work feeding surface adjacent to the periphery of one face of the work feeding disk is disposed substantially co-planar with the sewing machine work supporting surface and is opposed by a work presser device laterally opposite the stitching point. The work fabtie is thus advanced tangentially of the disk, and neither the Work fabric nor the presser device is moved by the.

work feeding mechanism perpendicular to the plane of the sewing machine work support, thus eliminating work.

presser device vibration which is a major source of the total noise and vibration incident to the operation of conventional sewing machines having the usual four motion type of work feeding mechanism.

It is within the scope of this invention to employ in place of an annular work feeding surface formed directly on the periphery of a disk, a series of contiguous feed elements constrained to move in an endless path and each formed with a work feeding surface which remains substantially co-planar with the sewing machine work supporting surface. When such series of feed elements are employed, the endless path may be formed noncircular so as to include a straight portion adjacent to the stitching point and disposed parallel to the normal line of feed of the work.

Fee

In the accompanying drawings:

FIG. 1 represents a vertical cross-sectional View of a sewing mechine to which one form of the work feeding mechanism of this invention has been applied,

FIG. 2 represents an enlarged top plan view of the portion of the work supporting bed of the sewing machine of FIG. 1,

FIG. 3 is an exploded perspective view of portions of the work feeding instrumentalities at one side of the stitching point of the sewing machine illustrated in FIGS. 1 and 2,

FIG. 4 is a cross-sectional view taken substantially along line 44 of FIG. 2 and including a fragment of the sewing machine work presser device,

FIG. 5 is a vertical cross-sectional view of the bed portion of a sewing machine similar to that illustrated in FIG. 1 but showing a different type of loop-taker and illustrating a modified form of the work feeding mechanism of this invention, and

FIG. 6 is a top plan view of the sewing machine bed portion illustrated in FIG. 5.

The sewing machine illustrated in FIG. 1 comprises a frame including a bed 11, a hollow standard 12 rising from the bed and surmounted by a bracket arm 13 terminating in a sewing head 14 overhanging the bed. A main drive shaft 15 journaled lengthwise in the bracket arm drives a shaft 16 journaled vertically in the standard by means of bevel gears 17, and a bed shaft 18 driven by bevel gears 19 from the shaft 16 carries a loop-taker 20' beneath the sewing head 14. A crank pin 21 carried on the main drive shaft 15 imparts movement to a needle thread take-up lever 22 and by means of a link 23 imparts endwise reciprocation to a needle bar 24 which is slidable in the sewing head and carries at its lower extremity a needle 25 for cooperation with the loop-taker 20 in the formation of stitches. A presser bar 26 slidable in the sewing head parallel to the needle bar carries at the lower extremity a work presser device 27. As is conventional in the sewing machine art, the presser bar is biased downwardly by a spring (not shown) the pressure of which may be adjusted by a knurled screw 28.

Fast on the main drive shaft 15 is a feed driving eccentric unit 30 which is preferably of the type well known in the art which may be adjusted as to eccentricity by man ual turning of the main drive shaft, as by means of a balance wheel pulley 31 on the main drive shaft, accompanied by depression of a locking plunger 32 carried on the bracket arm into engagement with the body of the eccentric unit 30. The feed driving eccentric unit imparts motion to a pitrnan 33 which is connected by means of a pivot pin 34 to a rock arm 35 fast on a feed driving rock shaft 36 journaled in the bed 11.

As illustrated in FIG. 2, the bed 11 above the looptaker is formed with an aperture 40 in which is accommodated a plate 41 secured in place by screws 42; The plate 41 in the top is formed with two shallow recesses 43 and 44 which are symmetrical in shape about a needle aperture 45 formed in the plate 41. Since each of the recesses 43 and 44 and the work feed means carried therein are alike save that one is the mirror image of the other. The following description of the recesses 43 and the mechanism therein will sufiice and corresponding parts of the recess 44 and mechanism therein will be indicated by corresponding prime number reference char acters in the drawings. The recess 43 is formed with a straight side wall portion 46- parallel to the direction of feed, a circular side wall portion 47, and a short side wall portion 48 blending the circular into the straight side wall portions.

Beneath the recess 43 the plate 41 is formed with a supporting block 50 formed with a bore 51 accommodating a hearing such as a conventional ball bearing 52. Journaled in the bearing 52 on a shouldered stud 53 is a disk 54 formed at the periphery with fine gear teeth 55. The disk 54 rests in the recess 43 and is formed with a central aperture 56 which accommodates the shouldered stud 53. A fastening screw 57 threaded into the shouldered stud constrains the disk on the bearing 52.

The disk 54 is formed with evenly spaced radial slots 60 through each of which passes a shouldered screw 61 threaded into a work feeding element 62. In plan view, as illustrated in FIG. 2 each work feeding element is preferably tapered slightly or formed trapezoidal in shape so as to accommodate assembly in annular array on the disk 54. Moreover, the corners of each work feeding element 62 are preferably rounded and the top surface 63 of the outer portion of each work feeding element is roughened as by serrations so as to provide a work feeding surface.

By means of the screw 61 each work feeding element 62 will be driven by turning movement imparted to the disk 54. Each work feeding element will, however, be free to partake of movement relatively to the disk 54 in a radial direction to the limit of the length of the slot 60 and also limited movement about the axis of the screw 61 to the extent permitted by clearance between adjacent work feeding elements. The work feeding elements 62 are constrained to move in a noncircular path as defined by the side wall portions 46, 47 and 48 by an inner camming plate 70 having a side wall 71 of similar but uniformly smaller shape to the recess side wall portions 46, 47 and 48. The inner camming plate 70 rests upon the disk 54 within the annular array of work feeding elements 62 and is formed with three protuberances 72 which seat in apertures 73 formed in a cover member 74 secured by screws 75 to the plate 41. The cover member 74, which may preferably be formed of transparent plastic, thus locks the inner camming plate 70 in position and is formed with a large central aperture 76 which exposes the needle aperture 45 and the work feeding elements 62 in the vicinity of the needle aperture for direct opposition by the presser device 27.

Referring to FIGS. 2 and 3, the plate 41 rearwardly of the needle aperture is formed with a slot 80 opening between the recesses 43 and 44. Through the slot 80 the gear teeth 55 of the disk 54 mesh with the corresponding gear teeth 55 of the work feed means disposed in the recess 44. As illustrated in FIG. 2, the axes of the bearing means 52-52 are preferably offset rearwardly of the needle aperture so that the gear teeth of the work feeding means will mesh at a point rearwardly of the stitching point and not conflict with the endwise penetration of the needle 25.

Carried beneath the bed 11 is a vertical axis overrunning clutch 90 of conventional design. Generally the overrunning clutch comprises a driven shaft 91 surmounted by a gear 92 and a driving collar 93 which is oscillatable about the driven shaft 91 and imparts turning movement to the shaft 91 and gear 92 only on one direction of oscillation. The driving collar 93 is connected by means of a link 94 to a rock arm 95 fast on the feed driving rock shaft 36. The gear 92 associated with the overrunning clutch meshes with the gear teeth 55' through a slot 96 formed in the plate 41, and by virtue of the meshing relation of the gear teeth 55 and 55', the work feeding elements 62 and 62 will be advanced together in step-by-step fashion in substantially parallel straight line paths beneath the pressure device 27.

The extent of movement of the work feeding elements during each needle reciprocation and thus the resulting stitch length may be selectively adjusted by regulation of the eccentricity of the adjustable eccentric 30.

A modified form of the work feeding mechanism of this invention is illustrated in FIGS. and 6. The portions of the sewing machine bed 11 illustrated in FIGS. 5 and 6 are adapted to cooperate with the standard 12,

4 bracket arm 13 and sewing head 14 illustrated in FIG. 1 and with the mechanism contained therein as heretofore described.

As illustrated in FIGS. 5 and 6 the sewing machine may be provided with a vertical axis loop-taker 100 carried on a loop-taker shaft 101 and driven by a gear 102 fast on the bed shaft 18 and a gear 103 meshing therewith and fast on the loop-taker shaft 101.

The bed 11 as illustrated in FIGS. 5 and 6 may be provided with a readily removable cover plate 104 over the loop-taker 100 for access thereto, at one side of which a throat plate 105 is secured by screws 106 to the bed and provided with a needle aperture 107. The throat plate at the opposite side from the cover plate 104 is formed with an arcuate side wall 108 which borders a circular opening 109 formed vertically in the bed 11.

Secured beneath the bed 11 is a bracket 111 which may support a bushing 112 for the bed shaft 18 closely adjacent to the loop-taker and which is formed with a web 113 beneath the circular bed aperture 109. In the web 113 is fixed a shoulder stud 114 on which is accommodated a conventional ball bearing 115 accommodated in a counterbore 116 formed in a work feeding wheel 117. The work feeding wheel is disposed with the upper face substantially flush with the top surface of the bed 11 and of the throat plate 105 and constrained on the stud 114 by the head of a fastening screw 118 threaded therein. Adjacent to the periphery, the upper face of the work feeding wheel is formed with an annular work feeding surface 120 which is preferably roughed as by knurling or serrations of which the crests may be raised slightly above the level of the upper surface of the bed 11 as illustrated in FIG. 5.

The presser device 27, which as illustrated in FIG. 5 may take the form of a conventional presser wheel, opposed the annular work feeding surface 120 laterally opposite the needle aperture 107. A conventional presser foot as illustrated in FIG. 1 may also be used, in which case it is preferable that the center of its work contacting area be arranged to occur laterally opposite the needle aperture 107.

Secured as by screws beneath the work feeding wheel is a ring 126 formed internally with gear teeth 127. The gear teeth 127 mesh with a pinion 128 fast on a driven shaft 129 of a conventional overriding clutch 130 which may be of similar construction and similar functioning to that indicated at 90 in FIGS. 1 and 2 and described herein above. Preferably a driven shaft 129 of the overriding clutch 130 is journaled in a bearing 131 set in the web 113 and the overriding clutch includes an oscillating collar 132 which drives the shaft 129 and associated pinion 128 only during oscillatory motion in one direction. A link 133 which is connected to the collar 132 and to a rock arm 134 on the feed rock shaft 36 imparts oscillatory movement to the collar 132. The angular increment of turning movement which is imparted to the work feeding wheel 117 during each needle reciprocation, and therefore, the resulting stitch length may be selectively varied by adjustment of the eccentricity of the eccentric 30.

In the modification illustrated in FIGS. 5 and 6, since the work fabrics will be engaged between the feed surface 120 of the work feeding wheel and the presser device 27 laterally of the stitching point, the work fabric will be advanced tangentially of the work feeding wheel periphery and it has been found that although the feed wheel rotates, little or no turning movement is imparted to the Work fabric and a substantially straight line of stitches results.

In the version illustrated in FIGS. 1 to 4, the arrange ment of the work feeding means on each side of the needle aperture 45 together with the provision of a substantially straight guide track for the work feeding elements 62 by the recess side walls 46 and 46 through that portion of the path of the work feeding elements which is opposed by the presser device, results in a substantially straight line of stitches being formed.

In both the form illustrated in FIGS. 1 to 4 and that illustrated in FIGS. 5 and 6, neither the work feeding mechanism nor the work fabrics manipulated thereby are moved in a direction perpendicular to the plane at which the work is supported on the sewing machine bed 11. The presser device 27, therefore, is not vibrated vertically at each stitch as it is when used with a conventional drop feed mechanism and as a result, a principal source vibration of a conventional sewing machine is eliminated.

Still another advantage attained in both the form illustrated in FIGS. 1 to 4 as well as in that illustrated in FIGS. 5 and 6 is the ease with which the starting edge of a fabric panel or a cross seam may be introduced to the work feeding mechanism. Since the work engaging surface 63 or 120 is disposed at a uniform level relatively to the sewing machine work supporting bed 11 prior to passing into opposition with the presser device 27, the starting edge of a fabric panel or the fabric at a cross seam will be always engaged first by the work engaging surface 63 or 120 and then by the presser device 27 whereas with drop feed mechanisms and with conventional wheel feed mechanisms the presser device is frequently encountered by the work fabric prior to the work feeding instrumentality. When this occurs, an operator assist is required and irregularities of stitch length invariably result.

What we claim herein is:

1. A work feeding mechanism for a sewing machine having a stationary frame formed with a flat work supporting surface and stitch forming instrumentalities defining a stitching point on said work supporting surface, said work feeding mechanism comprising a shiftable work engaging means, means for constraining said work engaging means in an endless annular path substantially flush with said sewing machine work supporting surface, means for imparting movement to said Work engaging means along said endless annular path in timed relation with the operation of said sewing machine stitch forming instrumentalities, and a presser device carried by said sewing machine frame and opposing only a portion of said work engaging means laterally opposite to said stitching point.

2. A work feeding mechanism as set forth in claim 1 in which said work engaging means is duplicated on opposite sides of said sewing machine stitching point, and in which the means for imparting movement to said duplicated work engaging means are drivingly interconnected.

3. A work feeding mechanism for a sewing machine having a frame formed with a flat work supporting surface and stitch forming instrumentalities defining a stitching point on said work supporting surface, said work feeding mechanism comprising a disk arranged substantially parallel to said sewing machine work supporting surface, means journaling said disk in said sewing machine frame on an axis perpendicular to said work supporting surface and disposed laterally of said stitching point, an annular work feeding surface carried on one face of said disk substantially flush with the work supporting surface of said frame, means for imparting turning movement to said disk in timed relation with the operation of said sewing machine stitch forming instrumentalities, a presser device carried by said sewing machine frame and opposing only a portion of said annular work feeding surface, said portion of the annular work feeding surface which is opposed by said presser device being disposed on an imaginary line along said work supporting surface which line intersects both said stitching point and said disk axis.

4. A work feeding mechanism for a sewing machine having a stationary frame formed with a flat work supporting surface and stitch forming instrumentalities defining a stitching point on said work supporting surface, said work feeding mechanism comprising a plurality of separate similar work feeding elements, means constraining said plurality of separate work feeding elements to move in an endless annular substantially planar path substantially flush with the work supporting surface on said sewing machine, means for imparting movement to said plurality of separate work feeding elements along said endless path in timed relation with said sewing machine stitch forming instrumentalities, and a presser device carried by said sewing machine frame and opposing said work feeding elements laterally opposite to said stitching point.

5. A work feeding mechanism as set forth in claim 4 in which said means constraining said plurality of work feeding elements to move in an endless annular path includes means for directing said work feeding elements in a substantially linear path parallel to the direction of feed of the work laterally opposite to said sewing machine stitching point.

6. A work feeding mechanism as set forth in claim 4 in which duplicate sets of said constrained plurality of work feeding elements are provided on set disposed on each side of said sewing machine stitching point, in which the means for imparting movement to each set of said work feeding elements are drivingly interconnected, and in which said presser device opposes both sets of work feeding elements.

7. A work feeding mechanism for a sewing machine having a frame formed with a fiat work supporting surface and stitch forming instrumentalities defining a stitching point on said work supporting surface, said work feeding mechanism comprising a shiftable work engaging means, means for constraining said work engaging means in an endless annular path substantially flush with said sewing machine work supporting surface, a presser device carried by said sewing machine frame and opposing only a portion of said work engaging means laterally opposite to said stitching point, and means for imparting motion to said work engaging means along said endless annular path comprising an overrunning clutch unit carried by said sewing machine frame and including an output shaft rotatable in only one direction operatively connected with said work engaging means, and, an oscillatable input collar, a feed driving eccentric operatively associated with said sewing machine stitch forming instrumentalities, and operative motion transmitting connections between said feed driving eccentric and said input collar of said overrunning clutch unit.

8. A work feeding mechanism for a sewing machine having a frame formed with a flat work supporting surface and stitch forming instrumentalities defining a stitching point on said work supporting surface, said work feeding mechanism comprising a disk arranged substantially parallel to said sewing machine work supporting surface, means journaling said disk in said sewing machine frame on an axis perpendicular to said Work supporting surface and disposed laterally of said stitching point, an annular work feeding surface carried on one face of said disk substantially flush with the work supporting surface of said frame, a presser device carried by said sewing machine frame and opposing said annular work feeding surface laterally opposite to said stitching point, a gear wheel carried on said disk concentric with said disk axis, an overrunning clutch unit carried by said sewing machine frame and including an output shaft, a pinion fast on said output shaft and disposed in mesh with said gear wheel, an oscillatable input collar, and means drivingly connecting said input collar to said output shaft upon only one direction of oscillation of said input collar, a feed driving eccentric operatively associated with said sewing machine stitch forming instrumentalities, and operative motion transmitting connections between said feed driving eccentric and said input collar of said overrunning clutch.

9. A work feeding mechanism for a sewing machine as set forth in claim 1 including a cover member carried on said sewing machine work supporting surface enclosing said shiftable work engaging means, said cover memher being formed with an opening exposing only that portion of said work engaging means opposed by said presser device.

10. A work feeding mechanism for a sewing machine having a frame formed with a fiat work supporting surface and stitch forming instrumentalities defining a stitching point on said work supporting surface, said work feeding mechanism comprising a rotary feed carrier journaled in said sewing machine frame on an axis perpendicular to said work supporting surface, a multiplicity of work engaging elements carried on said rotary feed carrier in annular array, means interlocking each of said work engaging elements for rotation with said rotary feed carrier and with capacity for limited radial movement of each of said work engaging elements independently relative to said rotary feed carrier, means for constraining said work engaging elements in an endless path including a straight segment extending in the direction of work feed laterally opposite to said stitching point, a presser device carried by said sewing machine frame and opposing said work engaging elements along said straight portion of said constrained path, and means for imparting motion to said rotary feed carrier in timed relation with said sewing machine stitch forming instr-umentalities.

11 A work feeding mechanism as set forth in claim 10 in which a pair of said rotary feed carriers are arranged one at each side of said sewing machine stitching point, the axes of said pair of rotary feed carriers disposed offset rearwar-dly of said sewing machine stitching point, a

gear wheel carried concentrically on each of said pair of frame formed with a recess in which said rotary feed carrier is disposed, side walls of said recess defining an outer race for constraining said work engaging elements in said endless path, a cover plate carried by said sewing machine frame and overlying said work engaging elements, a guide member disposed within said annular array of work engaging elements and defining an inner race for constraining said work engaging elements in said endless path, interengaging means on said guide member and on said cover plate for positioning said guide member relatively to said sewing machine frame, and said cover plate being formed with an opening exposing said straight portion of said constrained path of said work engaging elements for opposition by said presser device.

References Qited UNITED STATES PATENTS 611,405 9/1898 Casgrain l12-203 X JORDAN FRANKLIN, Primary Examiner.

RICHARD J. SCANLAN, JR., Examiner. 

1. A WORK FEEDING MECHANISM FOR A SEWING MACHINE HAVING A STATIONARY FRAME FORMED WITH A FLAT WORK SUPPORTING SURFACE AND STITCH FORMING INSTRUMENTALITIES DEFINING A STITCHING POINT ON SAID WORK SUPPORTING SURFACE, SAID WORK FEEDING MECHANISM COMPRISING A SHIFTABLE WORK ENGAGING MEANS, MEANS FOR CONSTRAINING SAID WORK ENGAGING MEANS IN AN ENDLESS ANNULAR PATH SUBSTANTIALLY FLUSH WITH SAID SEWING MACHINE WORK SUPPORTING SURFACE, MEANS FOR IMPARTING MOVEMENT TO SAID WORK ENGAGING MEANS ALONG SAID ENDLESS ANNULAR PATH IN TIMED RELATION WITH THE OPERATION OF SAID SEWING MACHINE STICH FORMING INSTRUMENTALITIES, AND A PRESSER DEVICE CARRIED BY SAID SEWING MACHINE FRAME AND OPPOSING ONLY A PORTION OF SAID WORK ENGAGING MEANS LATERALLY OPPOSITE TO SAID STITCHING POINT. 